21324431 has 8 divisors (see below), whose sum is σ = 21882960. Its totient is φ = 20768832.

The previous prime is 21324421. The next prime is 21324451. The reversal of 21324431 is 13442312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21324431 - 2¹⁴ = 21308047 is a prime.

It is a super-2 number, since 2×21324431² = 909462714947522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21324421) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25955 + ... + 26763.

It is an arithmetic number, because the mean of its divisors is an integer number (2735370).

Almost surely, 2^21324431 is an apocalyptic number.

21324431 is a deficient number, since it is larger than the sum of its proper divisors (558529).

21324431 is an equidigital number, since it uses as much as digits as its factorization.

21324431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1465.

The product of its digits is 576, while the sum is 20.

The square root of 21324431 is about 4617.8383471057. The cubic root of 21324431 is about 277.3059260404.

Adding to 21324431 its reverse (13442312), we get a palindrome (34766743).

The spelling of 21324431 in words is "twenty-one million, three hundred twenty-four thousand, four hundred thirty-one".